Liquid immersed ultrasonic transducers are commonly used for the atomization of the surrounding liquid. According to the construction of most such devices, the transducer is oriented with the vibrating surface (the surface producing the ultrasonic waves) directed upward. The upward directed ultrasonic waves propagate until their energy is transferred (as momentum) to the surface layer.
Because the vibrating surface of the transducer is horizontal and upward directed, impurities and precipatates in the liquid tend to settle on the transducer's vibrating surface. This creates a thermal insulation layer on the vibrating surface which progressively degrades transducer performance. Furthermore, the degree of thermal insulation provided by this progressive layering (coating) becomes sufficient to force the transducer to self-destruct from overheating.
Impurities in liquids have many sources. Impurities may be initially present in the liquid. Impurities may enter into the liquid because of the liquid contact with the air. Sometimes impurities may be produced from interactions between the transducer (or the ultrasonic waves produced thereby) and the liquid, or may be produced by interactions between the liquid and other components of the device (e.g. electric currents, pump mechanisms, etc.). Furthermore, impurities may aggregate.
Methods for removal of impurities and precipatants only partially alleviate this problem, because the efficient removal of the ultra-fine particles of impurities and precipatants is often an unreasonably expensive process.
The present invention presents a simple and cost effective method for partially (or completely) alleviating this precipatant and impurity settlement problem. Transducer efficiency losses associated with the present method are of low order.